Evaluate and simplify the following complex fraction. $\dfrac{ ~\frac {2}{3}~ }{ \frac{4}{-9}} = $
Answer: A fraction bar means "divided by". $\phantom{=}\dfrac{ ~\frac {2}{3}~ }{ \frac{4}{-9}} $ $=\dfrac{2}{3}\div \dfrac{4}{-9} $ $=\dfrac{2}{3}\cdot \dfrac{-9}{4} $ $=\dfrac{-18}{12}$ $=-\dfrac{3}{2}$ or $-1\dfrac12$